Ascorbate and glutathione metabolism during development and desiccation of orthodox and recalcitrant seeds of the genus Acer

2007 ◽  
Vol 34 (7) ◽  
pp. 601 ◽  
Author(s):  
Stanislawa Pukacka ◽  
Ewelina Ratajczak

The ascorbate–glutathione system was studied during development and desiccation of seeds of two Acer species differing in desiccation tolerance: Norway maple (Acer platanoides L., orthodox) and sycamore (Acer pseudoplatanus L., recalcitrant). The results showed remarkable differences in the concentration and redox balance of ascorbate and glutathione between these two kinds of seeds during development, and a significant dependence between glutathione content and acquisition of desiccation tolerance in Norway maple seeds. There were relatively small differences between the species in the activities of enzymes of the ascorbate–glutathione cycle: ascorbate peroxidase (APX, EC 1.11.1.11), monodehydroascorbate reductase (MR, EC 1.6.5.4), dehydroascorbate reductase (DHAR, EC 1.8.5.1), and glutathione reductase (GR, EC 1.6.4.2). At the end of seed maturation, ascorbic acid content and the activities of the above enzymes was about the same in both species The electrophoretic pattern of APX isoenzymes was also similar for both species, and the intensity of the bands decreased at the end of seed maturation in both species. When sycamore seeds were desiccated to a moisture content of less than 26%, there was a marked decrease in seed viability and an increase in the production of reactive oxygen species. During desiccation, Norway maple seeds had a more active defence system, which was reflected in a higher glutathione content, a higher glutathione redox status, a higher ascorbate redox status, and higher activities of APX, MR, DHAR, GR and GPX (glutathione peroxidase). During desiccation, sulfhydryl-to-disulfide transition into proteins was more intense in Norway maple seeds than sycamore seeds. All of these results suggest that, in orthodox seeds, the ascorbate–glutathione cycle plays an important role in the acquisition of tolerance to desiccation, in protein maturation, and in protection from reactive oxygen species.

2014 ◽  
Vol 7 (2) ◽  
pp. 207-215 ◽  
Author(s):  
C. Paciolla ◽  
A. Florio ◽  
G. Mulè ◽  
A.F. Logrieco

During their life cycle, plants can undergo simultaneous attack by different pathogens that produce various toxins. It is well known that in some plant-fungal interactions, mycotoxins play an important role in pathogenesis and induce a reactive oxygen species increase. Plants counteract the overaccumulation of reactive oxygen species by reinforcing their defence systems. The mycotoxins T-2 toxin (T-2) and beauvericin (BEA) are produced by some Fusarium species and have different chemical structures, mechanisms of action and biological activities. In this study, the individual and combined effects of these two toxins on defence systems, such as the ascorbate-glutathione cycle and peroxidases, were evaluated in cherry tomato shoots. Hydrogen peroxide content as an index of oxidative stress was also measured. Inhibitory effects on ascorbate peroxidase, dehydroascorbate reductase and ascorbate, and stimulatory effects on glutathione reductase, monodehydroascorbate reductase and reduced glutathione were observed when tomato plants were simultaneously treated with BEA and T-2. The trend of these biochemical parameters highlight the presence of a range of defence mechanisms activated by plants in response to mycotoxins. The interaction between BEA and T-2 resulting in synergistic and/or antagonistic effects on the studied defence systems is also discussed. It is concluded that the effects of these mycotoxins alone are not predictive of their combined effects.


Plants ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1586
Author(s):  
Svetlana Veselova ◽  
Tatyana Nuzhnaya ◽  
Guzel Burkhanova ◽  
Sergey Rumyantsev ◽  
Igor Maksimov

Reactive oxygen species (ROS) play a central role in plant immune responses. The most important virulence factors of the Stagonospora nodorum Berk. are multiple fungal necrotrophic effectors (NEs) (SnTox) that affect the redox-status and cause necrosis and/or chlorosis in wheat lines possessing dominant susceptibility genes (Snn). However, the effect of NEs on ROS generation at the early stages of infection has not been studied. We studied the early stage of infection of various wheat genotypes with S nodorum isolates -Sn4VD, SnB, and Sn9MN, carrying a different set of NE genes. Our results indicate that all three NEs of SnToxA, SnTox1, SnTox3 significantly contributed to cause disease, and the virulence of the isolates depended on their differential expression in plants (Triticum aestivum L.). The Tsn1–SnToxA, Snn1–SnTox1and Snn3–SnTox3 interactions played an important role in inhibition ROS production at the initial stage of infection. The Snn3–SnTox3 inhibited ROS production in wheat by affecting NADPH-oxidases, peroxidases, superoxide dismutase and catalase. The Tsn1–SnToxA inhibited ROS production in wheat by affecting peroxidases and catalase. The Snn1–SnTox1 inhibited the production of ROS in wheat by mainly affecting a peroxidase. Collectively, these results show that the inverse gene-for gene interactions between effector of pathogen and product of host sensitivity gene suppress the host’s own PAMP-triggered immunity pathway, resulting in NE-triggered susceptibility (NETS). These results are fundamentally changing our understanding of the development of this economical important wheat disease.


2007 ◽  
pp. 99-102
Author(s):  
F. R. Farkhutdinov

We studied effect of α tocopherol on clinical course and production of reactive oxygen species (ROS) in the whole blood in patients with community acquired pneumonia (CAP). The trial involved 70 patients with CAP. Generation of ROS was studied using the luminol dependent chemilumines cence (LDCL) method. Conventional treatment was given to all the patients. Besides this, 35 patients received α tocopherol. LDCL intensity of the blood was enhanced in all the patients. Treatment with α-tocopherol decreased ROS blood concentration and resulted in positive dynamics of clini cal and laboratory parameters. By contrast, patients on the conventional treatment maintained high LDCL intensity and there was slowly resolved course of inflammation in many cases. So, α tocopherol improved redox status in patients with CAP and increased efficiency of the treatment.


Antioxidants ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 105 ◽  
Author(s):  
Janků ◽  
Luhová ◽  
Petřivalský

Reactive oxygen species (ROS) have been recognized as important signaling compoundsof major importance in a number of developmental and physiological processes in plants. Theexistence of cellular compartments enables efficient redox compartmentalization and ensuresproper functioning of ROS‐dependent signaling pathways. Similar to other organisms, theproduction of individual ROS in plant cells is highly localized and regulated bycompartment‐specific enzyme pathways on transcriptional and post‐translational level. ROSmetabolism and signaling in specific compartments are greatly affected by their chemicalinteractions with other reactive radical species, ROS scavengers and antioxidant enzymes. Adysregulation of the redox status, as a consequence of induced ROS generation or decreasedcapacity of their removal, occurs in plants exposed to diverse stress conditions. During stresscondition, strong induction of ROS‐generating systems or attenuated ROS scavenging can lead tooxidative or nitrosative stress conditions, associated with potential damaging modifications of cellbiomolecules. Here, we present an overview of compartment‐specific pathways of ROS productionand degradation and mechanisms of ROS homeostasis control within plant cell compartments.


2018 ◽  
Vol 143 (6) ◽  
pp. 486-493 ◽  
Author(s):  
Ying Qu ◽  
Xue Bai ◽  
Yajun Zhu ◽  
Rui Qi ◽  
Geng Tian ◽  
...  

Leaves of Begonia semperflorens accumulate anthocyanins and turn red under low temperature (LT). In the present work, LT increased H2O2 content and superoxide anions production rate, causing significant increases in the activities of enzymes and contents of reduced components involved in the ascorbate-glutathione cycle (AsA-GSH cycle). As a result, LT-exposed seedlings increased the expression of genes involved in anthocyanin biosynthesis, and accumulated anthocyanin. Based on LT condition, application of N,N'-dimethylthiourea (DMTU) decreased reactive oxygen species (ROS) content, and unbalanced the AsA-GSH-controlled redox homeostasis. As a result, seedlings in the LT + DMTU group did not accumulate anthocyanin. Our results suggest that ROS may act as an important inducer in LT-induced anthocyanin biosynthesis.


Antioxidants ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 692
Author(s):  
Zhanhong Han ◽  
Zhenyu Wang ◽  
Yang Bi ◽  
Yuanyuan Zong ◽  
Di Gong ◽  
...  

Trichothecium roseum is an important postharvest pathogen, belonging to an alkalizing group of pathogens secreting ammonia during fungal growth and colonization of apple fruits. Fungal pH modulation is usually considered a factor for improving fungal gene expression, contributing to its pathogenicity. However, the effects of inoculation with T. roseum spore suspensions at increasing pH levels from pH 3 up to pH 7, on the reactive oxygen species (ROS) production and scavenging capability of the apple fruits, affecting host susceptibility, indicate that the pH regulation by the pathogens also affects host response and may contribute to colonization. The present results indicate that the inoculation of T. roseum spores at pH 3 caused the lowest cell membrane permeability, and reduced malondialdehyde content, NADPH oxidases activity, O2●− and H2O2 production in the colonized fruit. Observations of the colonized area on the 9th day after inoculation at pH 3, showed that the rate of O2●− production and H2O2 content was reduced by 57% and 25%, compared to their activities at pH 7. In contrast, antioxidative activities of superoxide dismutase, catalase and peroxidases of fruit tissue inoculated with spores’ suspension in the presence of a solution at pH 3.0 showed their highest activity. The catalase and peroxidases activities in the colonized tissue at pH 3 were higher by almost 58% and 55.9%, respectively, on the 6th day after inoculation compared to inoculation at pH 7. The activities of key enzymes of the ascorbate-glutathione (AsA-GSH) cycle and their substrates and products by the 9th day after fruit inoculation at pH 3 showed 150%, 31%, 16%, and 110% higher activities of ascorbate peroxidase, monodehydroascorbate reductase, dehydroascorbate reductase and glutathione reductase, respectively, compared to pH 7. A similar pattern of response was also observed in the accumulation of ascorbic acid and dehydroascorbate which showed a higher accumulation at pH 3 compared to the colonization at pH 7. The present results indicate that the metabolic regulation of the pH environment by the T. roseum not only modulates the fungal pathogenicity factors reported before, but it induces metabolic host changes contributing both together to fungal colonization.


2004 ◽  
Vol 279 (19) ◽  
pp. 20108-20117 ◽  
Author(s):  
Sara B. Cullinan ◽  
J. Alan Diehl

The accumulation of unfolded proteins elicits a cellular response that triggers both pro-survival and pro-apoptotic signaling events. PERK-dependent activation of NF-E2-related factor-2 (Nrf2) is critical for survival signaling during this response; however, the mechanism whereby Nrf2 confers a protective advantage to stressed cells remains to be defined. We now demonstrate that Nrf2 activation contributes to the maintenance of glutathione levels, which in turn functions as a buffer for the accumulation of reactive oxygen species during the unfolded protein response. The deleterious effects of Nrf2 or PERK deficiencies could be attenuated by the restoration of cellular glutathione levels or Nrf2 activity. In addition, the inhibition of reactive oxygen species production attenuated apoptotic induction following endoplasmic reticulum stress. Our data suggest that perturbations in cellular redox status sensitize cells to the harmful effects of endoplasmic reticulum stress, but that other factors are essential for apoptotic commitment.


2008 ◽  
Vol 20 (2) ◽  
pp. 269 ◽  
Author(s):  
Giuseppina Basini ◽  
Bussolati Simona ◽  
Sujen Eleonora Santini ◽  
Francesca Grasselli

A growing body of evidence indicates that the pro-oxidant/anti-oxidant balance inside the ovarian follicle plays an important role in folliculogenesis. Therefore, the aim of the present study was to assess the redox status of follicular fluids collected from different-sized swine follicles. We quantified the most important reactive oxygen species (ROS), namely superoxide anion (O2–), hydrogen peroxide and hydroperoxides (ROOH); in addition, we examined the activity of the detoxifying enzymes superoxide dismutase, catalase (CAT) and glutathione peroxidase and the total non-enzymatic antioxidant capacity as determined by the ferric-reducing anti-oxidant power assay. Our data demonstrate that oxidative stress does not affect follicle growth because O2– levels do not change during follicle development, whereas concentrations of H2O2 and ROOH are reduced (P < 0.05). Surprisingly, all non-enzymatic and enzymatic scavengers examined in the present study, except for CAT, demonstrated reduced activity during follicle development (P < 0.05). Taken together, these results suggest that other factors could be involved in ROS detoxification during follicle development.


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